//Closest Point to ...
D3DXVECTOR3 ClosestPtOnPolygon(D3DXVECTOR3 A, D3DXVECTOR3 B, D3DXVECTOR3 C,
D3DXVECTOR3 P)
{
D3DXVECTOR3 Rab = ClosestPtOnLine(A, B, P);
D3DXVECTOR3 Rbc = ClosestPtOnLine(B, C, P);
D3DXVECTOR3 Rca = ClosestPtOnLine(C, A, P);
D3DXVECTOR3 vDist0 = Rab - P;
float SqDist0 = D3DXVec3LengthSq(&vDist0);
D3DXVECTOR3 vDist1 = Rbc - P;
float SqDist1 = D3DXVec3LengthSq(&vDist1);
D3DXVECTOR3 vDist2 = Rca - P;
float SqDist2 = D3DXVec3LengthSq(&vDist2);
float Min = FLT_MAX;
D3DXVECTOR3 pClosest;
if(SqDist0 <= Min)
{
Min = SqDist0;
pClosest = Rab;
}
if(SqDist1 <= Min)
{
Min = SqDist1;
pClosest = Rbc;
}
if(SqDist2 <= Min)
{
Min = SqDist2;
pClosest = Rca;
}
return pClosest;
}
double Utils::DistPtFromLine( double ptx, double pty, double px, double py, double vx, double vy )
{
double t = ClosestPtOnLine(ptx, pty, px, py, vx, vy);
double qx = px + vx * t;
double qy = py + vy * t;
double dist = hypot(ptx - qx, pty - qy);
return dist;
}
